This invention relates to flexible gas-insulated transmission line cable, and more specifically relates to a novel structure for a factory-assembled reel of cable which has pressure-tight fittings at its opposite ends to enable the loading of an insulation gas into the cable when the cable is unreeled and placed in position for installation.
Flexible gas-insulated transmission line cable is well known wherein the cable consists of a central flexible conductor which is supported within an outer grounded housing which is filled with a suitable insulation gas, such as sulfur hexafluoride, under some positive pressure such as 3 atmospheres. This cable is then used in systems for the transmission of extremely high voltages, for example, 345 kV in electrical power line systems.
Flexible cable has the advantage that the cable may be wound on a reel and shipped in relatively long lengths which minimizes installation costs and assembly difficulties which exist in the case of rigid gas-insulated transmission line which is normally shipped in lengths of about 50 feet. By contrast, a flexible cable system may be wound on a reel and shipped in 100 meter lengths.